Hospital Morbidity Data Research Articles

First Eye Cataract Surgery and Hospitalization from Injuries Due to a Fall: A Population‐Based Study

To assess the association between first eye cataract surgery and hospitalization from injuries due to a fall in older adults at the population level. Retrospective population-based study. Western Australian Hospital Morbidity Data System and Western Australian mortality data. Six hundred individuals aged 60 and older hospitalized from injuries due to a fall between 2004 and 2008 in Western Australia. Hospital admission from injuries due to a fall. Of the 15,295 individuals who underwent cataract surgery in one eye only, 600 (3.9%) were involved in 625 hospital admissions from injuries due to a fall 1 year before (n = 273) or 1 year after (n = 352) first eye cataract surgery; 30% of these hospitalizations were for femoral neck fractures. Poisson generalized estimating equations confirmed 27% more (adjusted risk ratio = 1.27, 95% confidence interval = 1.04-1.56 P = .02) hospitalizations from injuries due to a fall in the year after first eye cataract surgery than in the year before. First eye cataract surgery was associated with more hospital admissions from injuries due to a fall in the year after cataract surgery than in the year before. Further research is needed to determine the underlying causes and reasons.

Country of birth recording in Australian hospital morbidity data: accuracy and predictors

Objective: Country of birth (COB) is an important determinant of health risks and outcomes. Despite the widespread use of hospital morbidity data for research, little is known about the quality of COB recording in these data. This study validated the recording of 40 COBs in Australian hospital morbidity data and identified factors associated with the recording accuracy. Methods: Questionnaire data from the 45 and Up Study were linked to records from the NSW Admitted Patient Data Collection (APDC), yielding linked records for 39,559 overseas-born people. Measures of agreement between self-reported COB from the 45 and Up Study (‘gold standard’) and COB as recorded in the APDC were calculated and logistic regression analysis was used to explore predictors of correct recording of COB. Results: On average, 81% of APDC records for overseas-born people had the correct COB recorded. Sensitivities varied between 61% (Germany) and 99% (Spain). Specificities exceeded 99.5%. Positive predictive values were greater than 90%, except for Hong Kong (72%), Ireland (85%), and Czechoslovakia (89%). Negative predictive values exceedved 98%, except for the United Kingdom (87%). Kappa values indicated good or excellent concordance between self-reported COB and APDC data (kappa 0.73 or greater). Where inaccurate, COB was mainly recorded as ‘Australia’ or ‘Inadequately described’. COB was recorded with greater accuracy in principal referral hospitals, public hospitals and hospitals in metropolitan areas. Accuracy decreased with duration of residence in Australia, increased with age at immigration, and varied according to COB. Conclusion: COB recording accuracy was generally high but varied according to hospital characteristics, country, and measures of acculturation.

Hospital morbidity data for determining spread of disease at diagnosis for colorectal cancer: A validation study

There is currently no routine collection of cancer stages in population-based data in Australia. This study evaluates the accuracy of International classification of diseases (ICD) codes for secondary neoplasms recorded in hospital morbidity data to assign spread of disease at diagnosis for colorectal cancer. The reference (gold) standard was the Australian clinicopathological stage (ACPS) documented by a treating colorectal surgeon and derived from histopathology and clinical findings. To allow comparison with stages derived from the hospital morbidity data (HMD), ACPS was mapped to the spread of disease (local, regional and distant). Sensitivity, specificity and positive-predictive values were calculated to compare the accuracy of stage derived from HMD. Data from both the reference standard and HMD were available for 499 patients. HMD slightly overestimated patients with local disease (62.3 vs 56.9%). There was a corresponding underestimation of regional and distant spread of disease. While sensitivity for regional and distant disease was moderate (66.4 and 71.4%, respectively), specificity was high (92.7 and 96.6%, respectively). ICD codes for secondary neoplasms in HMD are limited in their utility for determining the spread of disease for colorectal cancer. Clinicians need to ensure that clinical coders are provided with enough information to accurately code for spread of disease. We recommend reporting histopathology in a synoptic format which includes background information on the presence or absence of distant metastasis and the tumor node metastasis stage.

An assessment of burn injury hospitalisations of adolescents and young adults in Western Australia, 1983–2008

Background This study presents a 26-year epidemiological assessment of burn injury hospitalisations for people 15–29 years of age in Western Australia. Methods Linked hospital morbidity and death data for all persons hospitalised with an index burn injury in Western Australia for the period 1983–2008 were analyzed. Annual age-specific incidence rates were estimated. Poisson regression analyses were used to estimate temporal trends in hospital admissions. Results There were 6404 burn hospital admissions of which 76% were male. Males had hospitalisation rates 3.0 times that of females (95%CI: 2.8–3.2) and Aboriginal people had rates 2.3 times (95%CI: 2.1–2.5) that of non-Aboriginal persons. Hospitalisations for burn injury declined by 42% (95%CI: 35–47) for males and 21% (95%CI: 6–33) for females. Hospitalisations declined by 53% (95%CI: 35–63) for Aboriginal people, and by 35% (95%CI: 29–41) for non-Aboriginal people. Significant reductions were observed for flame and electrical burn hospitalisations. The major causes of burns in males were exposure to controlled fires and ignition of inflammable materials, with scalds the predominant cause of burn in females. Conclusions Downward trends in burn injury hospitalisations for both males and females 15–29 years of age were observed; however, males and Aboriginal persons have significantly elevated hospitalisation rates.

Maternal and foetal outcomes among pregnant women hospitalised due to interpersonal violence: A population based study in Western Australia, 2002-2008

BackgroundInterpersonal violence is responsible for more ill-health and premature death in women under the age of 45 than other preventable health conditions, but findings concerning the effects of violence during pregnancy on both maternal and foetal health have been inconsistent.MethodsA retrospective population-based cohort study was undertaken using linked data from the Hospital Morbidity Data Collection and the Western Australian Midwives' Notification System from 2002 to 2008. The aim was to determine the association between exposure to interpersonal violence during pregnancy and adverse maternal and foetal health outcomes at the population level.ResultsA total of 468 pregnant women were hospitalised for an incident of interpersonal violence during the study period, and 3,744 randomly selected pregnant women were included as the comparison group. The majority of violent events were perpetrated by the pregnant women's partner or spouse. Pregnant Indigenous women were over-represented accounting for 67% of all hospitalisations due to violence and their risk of experiencing adverse maternal outcomes was significantly increased compared to non-Indigenous women (adjusted odds ratio 1.53, 95% CI 1.21 to 1.95, p = 0.01). Pregnant women hospitalised for an incident of interpersonal violence sustained almost double the risk for adverse maternal complications than the non-exposed group (95% CI 1.34 to 2.18, p < 0.001). The overall risk for adverse foetal complications for pregnant women exposed to violence was increased two-fold (95% CI 1.50 to 2.76, p < 0.001).ConclusionsThe risk of adverse health outcomes for both the mother and the baby increases if a pregnant woman is hospitalised for an incident of interpersonal violence during pregnancy.

Hospitalisation for the surgical removal of impacted teeth: Has Australia followed international trends?

The aim of the study was to undertake a six-year analysis from 1999/00 to 2004/05, of the demographic characteristics of hospitalisations for the surgical removal of impacted teeth in Western Australia under general anaesthesia. Data for the current analysis was obtained from the Western Australian Hospital Morbidity Data System (HMDS). Gender, age, indigenous status, place of residence, type of hospital admitted, insurance status, and Diagnostic Related Group (DRG) cost estimates for the procedure were analysed. A total of 37.6% of all oral health-related hospitalisations in Western Australia over the six years were for the removal of impacted teeth. Admitted patients were predominantly females (58.8%) and very few Indigenous people were hospitalised (0.2%). The average age of patients was 21.4 years (sd=9.9). Metropolitan patients were hospitalised 1.5 times more than rural patients for this condition. The majority of patients were hospitalised at a private metropolitan hospital and were insured. The total cost of hospitalisation for this condition contributes to 27% of all the oral health condition-related hospitalisation costs. This study suggests that the hospital-based removal of impacted teeth in Western Australia is associated with factors such as indigenous status, age, gender and private hospital access along with insurance status raising interesting questions over the equity of provision of this service.

P2-195 A propensity score for predicting major adverse outcomes after total joint replacement in men

ObjectivePrioritisation of patients for total joint replacement (TJR) represents a challenge. The objective of this study was to construct a propensity score (PS) that both predicts and informs prioritisation of...

P2-196 Smoking, body weight, physical exercise and risk of lower limb total joint replacement in a population-based cohort of men

ObjectiveTo assess the associations of smoking, body weight and physical activity with the risk of undergoing total joint replacement (TJR) in a population-based cohort of men.MethodsA cohort study of 11...

Smoking, body weight, physical exercise, and risk of lower limb total joint replacement in a population‐based cohort of men

To assess the associations of smoking, body weight, and physical activity with risk of undergoing total joint replacement (TJR) in a population-based cohort of men. A cohort study of 11,388 men that integrated clinical data with hospital morbidity data and mortality records was undertaken. The risk of undergoing TJR was modeled on baseline weight, height, comorbidity, socioeconomic status, years of smoking, and exercise in 3 separate age groups, using Cox proportional hazards regressions and competing risk regressions (CRRs). Dose-response relationships between weight and risk of TJR and between smoking and risk of TJR were observed. Being overweight independently increased the risk of TJR, while smoking lowered the risk. The decreased risk among smokers was demonstrated in both Cox and CRR models and became apparent after 23 years of exposure. Men who were in the highest quartile (≥48 years of smoking) were 42-51% less likely to undergo TJR than men who had never smoked. Tests for trend in the log hazard ratios (HRs) across both smoking and weight quantiles yielded significant P values. Vigorous exercise increased the hazard of TJR; however, the association reached statistical significance only in the 70-74-year-old age group (adjusted HR 1.64 [95% confidence interval 1.19-2.24]). Adjusting for Deyo-Charlson Index or Elixhauser's comorbidity measures did not eliminate these associations. Our findings indicate that being overweight and reporting vigorous physical activity increase the risk of TJR. This study is the first to demonstrate a strong inverse dose-response relationship between duration of smoking and risk of TJR. More research is needed to better understand the role of smoking in the pathogenesis of osteoarthritis.

P2-98 Prior psychiatric hospitalisation predicts mortality in patients hospitalised with non-cardiac chest pain: a data linkage study based on the full Scottish population (1991–2006)

IntroductionNon-cardiac chest pain (NCCP) is considered a benign condition, associated with a low mortality rate. Contemporary population based studies describing outcomes in NCCP are lacking however. To our knowledge, the...

O5-5.6 Evaluation of the compression expansion and dynamic equilibrium theories using western Australian linked hospital morbidity and mortality data

IntroductionThree hypotheses have been advanced to predict changes in population health in countries experiencing low birth and death rates, and increasing expectation of life. Determining which of these best accounts...

P1-253 Long-term health risks after infective gastroenteritis: a population-based cohort study

IntroductionGastroenteritis presents a considerable burden on communities and health systems. In addition to the immediate health consequences long-term adverse sequelae have been associated with gastroenteritis; however, the risk and type...

Accuracy of hospital morbidity data and the performance of comorbidity scores as predictors of mortality

ObjectivesThe main objectives of this study were to validate the hospital morbidity data (HMD) and to compare the performance of three comorbidity adjusting methods in predicting 1-year and 5-year all-cause mortality in a male general hospital population in Western Australia (WA). Study Design and SettingPopulation-based data were integrated with WA-linked data system. Deyo–Charlson Index, Enhanced-Charlson Index, and Elixhauser's method measured comorbidity. Mortality was modeled using Cox regression, and model discrimination was assessed by Harrell's C statistics. ResultsThe HMD were most likely to identify major comorbidities, such as cancer, myocardial infarction, diabetes mellitus, and major operations. The presence of comorbidity was independently associated with an increased risk of adverse outcomes. All models achieved acceptable levels of discrimination (Harrell's C: 0.70–0.76). The Enhanced-Charlson Index matched the Deyo–Charlson Index in predicting mortality. Elixhauser's method outperformed the other two. Including information from past admissions achieved nonsignificant improvement in model discrimination. A dose-response effect was observed in the effect of repeated episodes on risk of 5-year mortality. ConclusionComorbidities diagnosed at different points in time may have different associations with the risk of adverse outcomes. More research is required to integrate the effect of repeated episodes in currently used methods that measure and adjust for comorbidity.

Trends in Hospital Admissions for Sunburn in Western Australia, 1988 to 2008

The objective of this study was to assess the trends in hospitalization for sunburn in Western Australia from 1988 to 2008. De-identified linked hospital morbidity data for all index sunburn admissions in Western Australia for the period 1988 to 2008 were analyzed. Poisson regression analysis was used to estimate trends in hospital admissions. Hospitalizations increased from 1.6 (95% confidence interval [CI] = 1.0-2.2) per 100 000 person years in 1988 to 2.7 (95% CI = 1.9-3.4) per 100 000 person years in 1997, declining thereafter to 1.5 (95% CI = 1.0-2.0) per 100 000 person years in 2008. Increased hospitalizations rates were estimated for adults 25 to 44 years and 65 years or older, with a significant decline estimated for children younger than 5 years; rates remained stable for all other age groups. This study found no significant overall reduction in sunburn hospitalizations over the 20-year study period. raise concerns about the sun-protective behaviors and skin cancer risk of the population in Western Australia.

Can we monitor heart attack in the troponin era: evidence from a population-based cohort study

BackgroundTroponins (highly sensitive biomarkers of myocardial damage) increase counts of myocardial infarction (MI) in clinical practice, but their impact on trends in admission rates for MI in National statistics is uncertain.MethodsCases coded as MI or other cardiac diagnoses in the Hospital Morbidity Data Collection (MI-HMDC) in Western Australia in 1998 and 2003 were classified using revised criteria for MI developed by an International panel convened by the American Heart Association (AHA criteria) using information on symptoms, ECGs and cardiac biomarkers abstracted from samples of medical notes. Age-sex standardized rates of MI-HMDC were compared with rates of MI based on AHA criteria including troponins (MI-AHA) or traditional biomarkers only (MI-AHAck).ResultsBetween 1998 and 2003, rates of MI-HMDC decreased by 3.5% whereas rates of MI-AHA increased by 17%, a difference largely due to increased false-negative cases in the HMDC associated with marked increased use of troponin tests in cardiac admissions generally, and progressively lower test thresholds. In contrast, rates of MI-AHAck declined by 18%.ConclusionsIncreasing misclassification of MI-AHA by the HMDC may be due to reluctance by clinicians to diagnose MI based on relatively small increases in troponin levels. These influences are likely to continue. Monitoring MI using AHA criteria will require calibration of commercially available troponin tests and agreement on lower diagnostic thresholds for epidemiological studies. Declining rates of MI-AHAck are consistent with long-standing trends in MI in Western Australia, suggesting that neither MI-HMDC nor MI-AHA reflect the true underlying population trends in MI.

Cardiovascular Mortality in Men with Erectile Dysfunction: Increased Risk But Not Inevitable

It is unclear whether men with erectile dysfunction (ED) ultimately die of cardiovascular (CV) causes. This study examined the causes of death in men with ED and their risk of CV death. Based on statutory death registrations and hospital morbidity data, the risk of CV death in men with ED in a linked-data study was assessed against the CV mortality risk in a reference male population. Deaths from CV causes as proportions of all deaths. Age-specific rate, mortality rate ratio (MRR), standardized mortality rate ratio (SMRR), and adjusted hazard ratio (HR). CV mortality was 4.0%. Compared with the reference population, the risk of CV death was higher in men with ED (SMRR 2.2; 95% confidence interval [CI] 1.6, 3.0). Risk of CV mortality was higher in men with CV disease prior to ED (adjusted HR 1.7; 95% CI 1.1, 2.6) or with history of hospital admissions for CV events (adjusted HR 2.2; 95% CI 1.3, 3.8), compared with those without the respective history. MRR was significantly increased in the 40-69 years age group (MRR 4.1; 95% CI 3.2, 5.2). The median time interval between manifestation of ED and CV death was 10.0 years. A greater proportion of deaths from oncological than from CV causes (25.0% vs. 10.8%) occurred within the first 5 years of the manifestation of ED. Although the risk of CV mortality is greater in men with ED, almost as many men die of oncological as of CV causes, with a higher proportion of oncological deaths occurring sooner subsequent to the first manifestation of ED.

Efficacy of prophylactic treatment with selective serotonin reuptake inhibitors for depression after open-heart surgery

The aim of the present study was to evaluate the efficacy of prophylactic treatment with selective serotonin reuptake inhibitors (SSRIs) in female patients at high risk of suffering depression after cardiac surgery. Female patients (n = 58; group I) who were over 70 years of age or who had undergone emergency surgery were administered prophylactic treatment with paroxetine immediately after surgery. The hospital mortality and morbidity data of these patients were compared with those of 59 patients (group II) without prophylactic medication. The Center for Epidemiological Studies Depression Scale (CES-D) score at 10 days after surgery was significantly lower in group I (15.2 ± 7.8) than in group II (21.8 ± 7.5, P = 0.0018). The incidence of depression (I: 12.1% vs II: 64.4%, P < 0.0001) and pneumonia (I: 0% vs II: 10.2%, P = 0.0127) were significantly lower in group I than in group II. In addition, the duration of postoperative hospital stay was significantly shorter for group I than for group II (I: 15.9 ± 56.5 vs II: 23.4 ± 20.5 days, P = 0.0102). The hospital mortality rates were similar. The quality of life of patients with depression after open-heart surgery is poor. The early administration of prophylactic medication is therefore necessary for those patients at risk for developing depression.

A 26-Year Population-Based Study of Burn Injury Hospital Admissions in Western Australia

The aim of the study was to use state-wide health administrative data to assess the incidence, temporal trends, and external cause of burn injury-related hospital admissions and mortality in Western Australia from 1983 to 2008. Linked hospital morbidity and death data for all persons hospitalized with an index burn injury in Western Australia for the period 1983-2008 were identified. Annual age-specific incidence and age standardized rates were estimated. Poisson regression analyses were used to estimate temporal trends in hospital admissions and mortality. Zero-truncated negative binomial regression analysis was used to identify factors associated with hospital length of stay. From 1983 to 2008, there were 23,450 hospitalizations for an index burn injury. Hospital admission rates declined by an average annual rate of 2% (incidence rate ratio [IRR], 95% confidence interval [CI] = 0.983, 0.981-0.984), and burn-related mortality declined by an average annual rate of 2% (IRR, 95% CI = 0.98, 0.96-1.01). Aboriginal people while having significantly higher hospitalization rates than non-Aboriginal people experienced a greater 26-year decline in hospitalizations of 58% (IRR, 95% CI = 0.42, 0.37-0.48) compared with 32% (IRR, 95% CI = 0.68, 0.65-0.71) for non-Aboriginal people. Children younger than 5 years, 20- to 24-year-old men, and adults older than 65 years remain at high risk for burn injury, and males continue to be hospitalized twice as frequently as females. The results demonstrate declines in burn injury hospitalizations and mortality in both Aboriginal and non-Aboriginal populations. Continued research is required of the impacts of medical interventions and the burn pathway of identified high-risk populations.

A Study of Burn Hospitalizations for Children Younger Than 5 Years of Age: 1983–2008

Burn injury is a leading cause of emergency department visits and hospitalizations for young children. We aimed to use statewide linked health administrative data to evaluate the incidence, temporal trends, and cause of burn injuries for children younger than 5 years hospitalized for burn injuries in Western Australia for the period 1983-2008. Epidemiologic analysis of linked hospital morbidity and death data of children younger than 5 years hospitalized with an index burn injury in Western Australia for the period 1983-2008. Poisson regression analyses were used to estimate temporal trends in hospital admissions and the external cause of the burn injury. From 1983 to 2008, there were 5398 hospitalizations for an index burn injury and 3 burn-related deaths. Hospital admission rates declined by an average annual rate of 2.3% (incidence rate ratio: 0.977 [95% confidence interval: 0.974-0.981]). More than half of the admissions were for scald burns. Hospitalizations declined for injury caused by scald, flame, contact, and electrical burns; however, the number of hospital admissions increased for chemical burns during the study period. The burn-injury hospitalizations reported in this study were preventable. Most burns occurred in the home and resulted from exposure to a household hazard. Further effort needs to be devoted to burn prevention and safety strategies, particularly in relation to scalds, to further reduce the incidence of burn injury in young children.

Population Trends of Recurrent Coronary Heart Disease Event Rates Remain High

Survivors of nonfatal coronary heart disease (CHD) can reduce their risk of further events by various preventive interventions. The impact of such measures as delivered over 11 years, on population rates of subsequent major CHD events, has not been extensively studied. This study determined population trends in the prevalence of clinically manifest CHD and the proportion of major CHD events that occur in this population. A population longitudinal person-based event-linked file of CHD extracted from State Hospital Morbidity Data and Death Registry for 1980 to 2005 was used to identify, for each year from 1995 to 2005, survivors who had a hospitalization for CHD over the previous 15 years (population with established CHD), and to examine the occurrence of CHD death and hospitalization with a principal diagnosis of myocardial infarction in both populations with and without established CHD. The average annual age-standardized prevalence of CHD in the Perth metropolitan region (population 1.6 million) was 28 373 (8.8%) in men and 14 966 (4.0%) in women. Age-specific prevalence increased exponentially with age, from <1% in 35 to 39 age group to 42% in 80 to 84 age group in men and half that in women. The percentage of total CHD events (n=28 941) that occurred in the population with established CHD was approximately 43% in both men and women, 55% and 51%, respectively, for CHD death and 35% and 36% for nonfatal myocardial infarction. More than 40% of major CHD events annually occur in persons with manifest disease, highlighting the imperative to implement systems of care that support effective secondary prevention.